The tuberculosis epidemiological situation was studied among the children of the Udmurt Republic and the tuberculosis morbidity rates in children, the risk of primary infection, and the infection rates were predicted by the Bayes procedure. To study the impact of chemoprophylaxis on the incidence of tuberculosis in children, the risk of its primary infection, and the infection rates, the authors used the multivariate statistical method--hypotheses theorem (the Bayes formula). The application of the hypotheses theorem has shown that if the cohort of children who had chemoprophylaxis in 2007, they should receive it at the same rate as in 2002, which is 30% greater, the morbidity rates in children should show a 1.1-fold reduction.